Resiliently pivoted back rest



April 3, 1951 R. J. FREEMAN 2,547,455

RESILENTLY PIvoTED BACK REST Filed Aug. 12'; 1944 s sheets-sheet. 1

I lN'vl-:NTOR POLA/v0 L/ FREEMAN M 5T MM ATTORN EY pr 39 QS R. J. FREEMAN 547,455

RESILENTLY PIvoTED BACK REST Filed Aug. 12, 1944 :s sheets-sheet 2 ATTORNEY April 3, 1951 R. J. FREEMAN 2,547,455

- RESILENTLY PIVOTED BACK REST Filed Aug. 12, 1944 `3 Sheets-Sheet 5 l xNvENToR Pom/v0 d. fPff/wfQ/v MEM ATTORN EY Patented Apr. 3, 1951 UNITED STATES PATENT OFFICE Claims. l

This invention relates to improvements in posture chairs, and more particularly in the back rest mountings therefor.

The posture chairs heretofore manufactured are constructed so that the back rest is either rigidly secured to the back post, or is hinged thereto in such a way that the movement of the back rest can not be satisfactorily controlled. In some cases a spring mechanism has been employed, in an attempt to bring the back rest into approximate back-engaging position, the spring mechanism serving to return the back rest to what might be described as normal hack-engaging position when pressure is removed from the back rest.

One object of this invention is a back rest for a posture chair which is so mounted that it can be quickly and simply adjusted to suit the individual postural requirements of different occupants.

Another object is a posture chair having a back rest which is so pivoted that it lprovides a cushioning effect when the occupant leans against the back rest.

Another object is a posture chair having a resiliently pivoted back rest.

Another object is a mechanism, including a pivotal mounting, for a back rest, which mechanism is assembled as a unitary structure, and which can be introduced between the back post and the back rest of a chair to eifect cushioned pivotal movement of the back rest.

Another object is a posture chair having a revoluble seat, and simplied adjusting mechanism therefor.

Another object is a posture chair which can be manufactured at low cost, without any sacrifice in strength or durability.

Another object of this invention is a posture chair of relatively few and simple parts, and which can be fabricated'out of common and inexpensive stock materials.

Other objects will appear from the detailed description.

The posture chair embodying the present invention is so constructed that the seat frame not only revolves relative to the pedestal, but may also be adjusted up and down, and back and forth, relative to the back post; the back post in turn being selectively adjustable for tilting movement responsive to various body pressures applied to the baci: rest; and the back rest in turn being adjustable at different heights relative to said back standard steel sheets of pre-determined gauge and the pedestalor base is'so designed that it may be made of steel tubing of various standard sizes as selected.

In the drawings comprising three sheets of seven figures, numbered Figs. 1 to 7, both inclusive, one embodiment of the invention is shown.

Fig. l is a side view of one form of posture chair, embodying the invention.

Fig. 2 is a plan view thereof.

Fig. 3 is a vertical cross sectional view, taken along the line 3-3 of Fig, l, looking in the direction of the arrows, with some of the parts partially broken away.

Fig. 4 is a top view of the undercarriage.

Fig. 5 is a rear View of the upper end of the back post assembly.

Fig. 6 is a vertical cross sectional view, taken along the line 6-6 of Fig. 5, looking in the direection of the arrows, and

Fig. 7 is a fragmentary sectional view taken on the line l-l of Fig. 4.

Like reference characters designate corresponding parts, throughout the several figures of the drawings.

The posture chair (Fig. l) consists of a plurality of legs 55, forming a pedestal, support or base, an undercarriage 36 (Fig. 3), mounted for rotation upon the base, a seat 3i] adjustably secured to the undercarriage, a back post 25 yieldably supported by the undercarriage, and a resiliently pivoted back rest I4 adjustably secured to the back post.

The pedestal or base preferably comprises a series of legs 55, made from sections of steel tubing which are outwardly bent, so that the bent tubes when assembled form the outspreading legs of a supporting base. The upper ends of the legs are locked together by means of the upper and lower steel hub plates 52 (Figs. 1 and 3), having spaced openings formed therein cooperating with the upper ends of the legs. The hub plates 52 are attached to a hub 5I, the hub being rabbeted to form a seat or shoulder for each plate 52. The hub 5l is riveted over or peened at 54 to secure the upper and lower plates 52 in place. The upper end of each leg 55 may be notched (Fig. 3) to form a cutout 56, and a bent over lug 53, may depend from each opening of the upper hub plate 52, to register in the cutout 56, the upper ends of the legs 55 passing through the spaced openings in the lower hub plate 52 and being drawn against the upper hub plateA 52 by means of suitable retaining bolts ll, which engage the female threaded upper ends of theA legs 55 (Fig. 3). The bent over lugs 53 register in the cutouts 5E, to keep the legs from turning.

A locking pin orvtrigger 58 is mounted in a housing 5l. A coiled spring Eil is mounted upon the trigger 58, between the wall of the housing 5l and a Washer 50. The washer 5!! is retained upon the trigger 58 by means of a pin 5I which engages in a hole in the trigger 58. The inner 3 end of trigger 58 projects through a hole in the hub 5I, so that when the trigger 58 is released it may register in one of a series of spaced holes 50 formed in the central tube 49 which supports the rotatable undercarriage 36 in the hub 5I of the pedestal' or base.

Rotatable undercarriage 3B, includes a U shaped metal frame 31 (Fig. 3), shaped out of sheet steel or the like. Frame 31 is reinforced near its wing tips by another U shaped metal member 39. The metal member 39V is secured. to the frame 31 in any preferred manner,v as by means of a series of rivets (Figs. 3 and 4). The wing tips of frame 31 are outwardly bent to form a pair of flanges or ears 38, which slidably register in the spaced guide channels 32 (Figs. 3 and 4). The guide channels 32 are in turn secured to the cross braces 29 in any suitable manner, as by means of a series of rivets 35. A female threaded sleeve 82, welded or otherwise attached to the metal frame 31 of the undercarriage 36, is provided with an adjustable screw bolt 63. Bolt 63 when tightened engages the wall of guide channel 32 or other part of frame 3I, to lock the frame 31 of the undercarriage 36, against change of adjustment relative to frame 3l of seat 30.

The cross braces 29 are provided with a series of holes 33 for receiving suitable means such as the wood screws 34, for attaching the frame 3i to :i

the underside of the seat 30 (Fig. 3). The seat 33 may be adjusted relative to the rotatable underca-rriage 36, by sliding the seat 38 to move the guide channels 32 with respect to the flanges 38 of the undercarriage 36.

The U-shaped members 39 and 31 are provided with centrally disposed openings 42 and 44 for receiving upper bushing 43, and lower bushing 45, respectively. Bushings 43 and 45 are press tted in the openings 42 and 44 in the U-shaped members. A short tube 46 is press fitted in the upper end of the outer tube 49, so as to extend beyond the upper end of the outer tube. Inner tube 46 and outer tube 49 in conjunction, form a seat whereon the upper bushing 43, and therefore the undercarriage 36, is rotatably supported. Bushings 43 and 45 form the bearings for the undercarriage 33, bushing 43 being the load-carrying bearing, and bushing receiving the side thrust. Bushings 43 and 45 are preferably of the self-lubricating type, which not only allows undercarriage 3S to revolve freely, but also reduces wear upon the moving parts. A washer 64 ts over the end or the tube 43 and is held in position by a Cotter pin 48 passing through the holes 'i extending through the wall of the upper end of the tube 46 (Figs. 3 and 4). The seat 351 and rotatable undercarriage 36, can be detached from the outer tube 49 by merely releasing the cotter pin 48. Similarly the seat 33, undercarriage 35, and outer tube 49 can be detached from the pedestal, by merely releasing the locking pin 58 and lifting the seat 30 until outer tube 49 disengages the hub 5| of the pedestal.

The U-shaped bracket I5 is attached by suitable fastening means, such as the wood screws I, to a back rest I4, which may be any suitable material such as wood. Back rest I4 may be upholstered. A stud I8 is pivotally secured to the bracket I5 as by means of a retaining pin I1. A yieldable member I9 which may be of any suitable elastic material such kas vulcanized rubber, is mounted upon the stud I8 and rests against or abuts the face of the bracket I5.

Y -Stud I8 includes a circular intermediate section' threaded at 22, a reduced squared shoulder portion 23, and a reduced end section threaded at 24. The member I9 which consists of rubber or like elastic material, is yieldable to provide a cushioning eifect. Member I9 is variously compressible between the face of the bracket I5 and the washer 20 under tension applied to the washer 20 by means of the threaded washer 2I which is adjustable upon the threaded portion 22 of the stud I8, As the washer tension is increased the cushioning limits of the member I9 are reduced accordingly. The guide member 25 is provided with a squared opening for mounting the guide member upon the squared shoulder portion 23 of stud I8, The back rest I4 is adjustably supported in the elongated slot 21 of the back post 26, by means of the handwheel 28, which clamps the back post guide. member 25 supported upon the squared shoulder portion 23 of stud I8, against the back post 26, by turning the handwheel 28 upon the threaded portion 24 of the stud I8. Thus the position of the back rest I4 may be adjusted with respect to back post 25, by the manipulation of the handwheel ZiLand the movement of the guide member 25 and of the stud I8, relative to the elongated slot 21 formed in the back post 23 (Figs. 5 and 6).

Back post 26, which may be shaped to conform in general to the body posture, is attached to a metal bracket 35, which is pivotally mounted at 66 upon the U-shaped metal frame 31 of the rotatable undercarriage 36, so that the back post 26 may pivot about the pivot 6G, against the tension of acoiled spring 89, mounted upon a threaded bolt B8, which bolt passes through the upper U-shaped metal member 39, and carries a threaded handwheel 13 to adjust the tension of the coiled spring 69. A cup shaped washer 13 (Figs. l and '7), is mounted upon the bolt 68 to receive and center the upper end of coiled spring 69. The spacer washer 61 is mounted upon bolt 68 to limit the return movement of the back post 2G. The surface of the U-shaped member 39 in the region of the opening for the bolt 68 is made convex at 12 (Fig. 7) to form a rounded bearing surface for the head of bolt 68 to pivot upon, when the back post 28 moves to adjust itself to the occupants posture.

The natural resilience of the rubber of which the cushion I9 is fabricated, causes the cushion I9 to co-operate with the pivoted stud I8, the bracket I5 of the back rest I4, and the pivoted back post 26, in such a manner, that the back rest automatically and quite naturally tends to respond to every change in pressure resulting from any change in the occupants posture thus adjusting the back rest to back engaging position.

The pedestal can be detached by releasing trigger 58 and lifting the seat 38 and rotatable undercarriage upwards, until the outer tube 49 disengages the hub 5I. The outer tube 49 can be de'- tached from the undercarriage by withdrawing the cotter Din 48.

To adjust the seat 30 relative to the back post 26 and back rest I4, the bolt 63 is released, and the seat 39 is moved in or out thus changing the distance between seat 30 and the back post 26. To adjust the height of the seat from the floor the trigger 58 is withdrawn from the hole 5I) in the outer tube 49, the seat is raised or lowered and the trigger released to engage another hole 50 in the tube 49.

To adjust the height of back rest I4, the handwheel 28 is released and the back rest is raised or lowered, thus moving the back post guide member 25, relative to the elongated slot 21, and

handwheel 28 is turned, to lock the back rest Il in the new position. To adjust the yieldability of the back rest I4 to the occupants posture, the adjustable washer 2| is screwed along the threaded portion 22 of the stud I8, thus varying the spacing between the washer 20 and the bracket I5, thereby changing the degree of compressibility of the yieldable member I9 and therefore of the back rest I4. To change the support furnished by the back post 26, the handwheel 19 is rotated to vary the tension of the coiled spring 69.

What is claimed is:

1. A posture chair comprising a back post, a back rest, a pivotal connection fastened therebetween for cushioning the movement of said back rest, said pivotal connection including a rigid member mounted on the back rest, a stud mounted on the back post and a resilient bushing supported by said stud, and means co-acting with said stud to compress said bushing against said rigid member to vary the resilience of said bushing.

2. A posture chair comprising a back post, a back rest, a pivotal connection fastened therebetween including a rigid member mounted on said back rest and a stud mounted on said back post, a resilient bushing slidably mounted on said stud and abutting said rigid member to cushion the movement of said back rest upon said pivot, and a washer threadably mounted on said stud to compress said bushing against said rigid member to variously regulate the resilience of said bushing.

3. A posture chair comprising a back post, a back rest, a pivotal connection attached therebetween, said pivotal connection including a stud mounted on said back post, a rubber bushing supported by said stud, said bushing being operable when compressed to cushion the movement of said back rest about said pivot, and means including said back rest co-acting with said stud to compress said bushing.

4. A posture chair` comprising a back post, a back rest, a pivotal connection mounted therebetween, said pivotal connection including a stud mounted on said back post and a rigid member mounted on said back rest and disposed transverse said stud, a rubber bushing mounted upon said stud, said rigid member bearing against one end of said bushing, said bushing cushioning the movement of said back rest about said pivot, and a washer mounted for movement along said stud and relative to said rigid member to variously compress said bushing.

5. A posture chair comprising a back post, a stud detachably secured to said back post, a back rest pivoted to the stud on a horizontal axis to effect rearward tilting movement of the back rest, a stop mounted on said back rest, a vulcanized rubber bushing slidably mounted upon said stud to engage said stop, said bushing cushioning the movement of said back rest when tilted, and a washer mounted to move along said stud to compress said bushing against said stop.

6. In a back rest mounting and in combination, a stud, a bracket having a centrally disposed opening formed therein large enough to freely accommodate one end of said stud, said stud end passing through said opening, said bracket being pivotally supported upon said stud end, a rigid member mounted upon said stud in spaced relation to said bracket, a vulcanized rubber bushing positioned between said bracket and said rigid member and compressible when engaged therebetween to oppose and cushion any pivotal movement of said bracket relative to said stud, and said rigid member being movable axially along said stud to variously compress said bushing against said bracket.

7. A cushioning assembly unit comprising a bracket, a stud, a stop adjustably mounted upon one end of said stud, said bracket being rockably mounted upon the opposite end of said stud, an elastic bushing mounted upon said stud and compressed between said stop and said bracket, and said bracket in rocking being operable to compress said bushing to cushion the movement of said bracket.

8. In a posture chair and in combination a back post member, a back rest member, a stud pivotally connected to one of said members and fxedly secured to the other of said members, a resilient bushing on said stud bearing against the member to which the stud is pivotally connected, and means to regulate the compressibility of said bushing.

9. In a posture chair and in combination a back post member, a back rest member, a stud pivotally connected to one of said members and xedly secured to the other of said members, a compressible rubber bushing on said stud bearing against the member to which the stud is pivotally connected, and means to regulate the compressibility of said rubber bushing.

10. A cushioning assembly unit comprising a bracket, a stud, a stop adjustably mounted near one end of said stud, said bracket being rockably mounted upon the opposite end of said stud, a compressible rubber bushing mounted upon said stud and compressed between said stop and said bracket, and said bracket in rocking being operable to compress said bushing against said stop to cushion the movement of said bracket.

ROLAND J. FREEMAN.

REFERENCES CITED The following references are of record inV the le of this patent:

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